The long range goal is to provide an understanding of the role of oxidation and transport mechanisms in human senile cataract. We have recently succeeded in growing human lens epithelial cells (HLE) in tissue culture through several passages in which the cells retain lens specific characteristics by expressing crystallins and undergo fiber cell differentiation. This promising model system will be used for a systematic study of the expression of crystallins and plasma membrane proteins by a combination of biochemical, immunofluorescent, immunochemical and SDS PAGE electrophoresis techniques. Synthesis of proteins in primary and subsequent subcultures will be studied by the incorporation of radiolabeled amino acids. Other specific aims include: the determination of glutathione, amino acid and cation compositions in HLE cells; a number of key enzymes of carbohydrate and glutathione metabolism and their role in defending the lens against oxidative damage; the relative role of catalase and glutathione redox cycle in the detoxification of H202 which is normally present in the aqueous humor. Additional objectives are concerned with studies on transport of 86Rb and amino acids; membrane ATPase and the effect of H202; and hyperbaric oxygen and other oxidants on these parameters. Since cells undergoing differentiation are more vulnerable to oxidation, efforts will be made to examine the steps of this differentiation process under normal conditions and under conditions of oxidative stress. Studies that relate to aldose reductase inhibitors in HLE cells are to determine the efficacy of various inhibitors as potential anticataractogenic agents inhuman diabetes.